<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
   <head>
       <title>Form表单</title>
     </head>

   <body>
       <form action="${pageContext.request.contextPath}/demo" method="post">
         <%--使用EL表达式取出存储在session中的token--%>
         <input type="hidden" name="token" value="${token}"/>
         用户名：<input type="text" name="username">
        <input type="submit" value="提交" id="submit">
      </form>
   </body>
 </html>